1. Field of the Invention
The present invention relates to a document feeding device for feeding documents one by one for reading. The present invention also relates to an image forming apparatus including the document feeding device.
2. Description of Related Art
Conventionally, in order to copy or scan a plurality of sheets of documents at high speed, some types of image forming apparatuses such as a scanner, a multifunction peripheral, and a fax machine have been provided with a document feeding device. The document feeding device feeds documents placed on a document tray one by one to a reading position automatically and continuously.
For example, there is known an image forming apparatus provided with a document feeding device and having the following configuration. Specifically, the image forming apparatus, in which a series of documents set in automatic document feeding means are sequentially conveyed, an image on the conveyed document is read and stored in storage means, and an image is formed by reading image information stored in the storage means, includes: first setting means for setting a document page of the image information already stored in the storage means, when a jam of a document being conveyed by the automatic document feeding means has occurred; second setting means for setting a document page from which the reading of the series of documents is resumed; and control means for, when the series of documents are set again in the automatic document feeding means, performing control so as to idle-eject documents up until the document page set by the first setting means, start reading an image from the document page set by the second setting means, and store the image in the storage means. This configuration attempts to enable accurate and easy return processing from a paper jam that has occurred during the conveyance of documents.
First, the document feeding device is provided with a rotary member (for example, roller) for feeding documents. The rotary member is in contact with a topmost document. Then, the rotary member is driven, thereby feeding the document (performing sheet feeding).
Here, the amount of documents placed on the document feeding device varies. Accordingly, the rotary member that feeds documents is configured to be swingable (movable) in the vertical direction to some degree. However, if the rotary member is positioned low before documents are set, there may occur such a drawback that the number of placeable document sheets becomes smaller. Further, such a drawback that documents cannot be placed appropriately may also occur. To address this, in some cases, the initial operation of the rotary member is performed. For example, in the initial operation, the rotary member is lifted up to an upper (upper limit) position by using a motor or a solenoid.
However, when there are set documents, the initial operation is difficult to perform. This may prevent the initial operation from being performed appropriately. To address this, when there are set documents at the time of the initial operation, a reset request making a request to remove documents from the tray and place the documents again is displayed on, for example, a liquid crystal panel of the image forming apparatus or the like. Note that, when the documents have been removed temporarily, the initial operation is performed.
It is unclear whether or not the initial operation has been performed properly before the power supply is stopped. Accordingly, when the power supply to the document feeding device is resumed, in some cases, the initial operation is performed as one of initialization operation steps. For example, the power supply is resumed when main power has been turned on or when a power saving mode such as a sleep mode has been canceled.
However, conventional document feeding devices do not distinguish between the case where the power supply is resumed by the cancellation of the power saving mode and the case where the power supply is resumed by the turning-on of the main power. Accordingly, even when there is no need to display the reset request because the power supply is resumed by the cancellation of the power saving mode, the reset request is displayed if there is a set document. This is problematic in that a user is forced to bear unnecessary trouble (removal and reset of documents). Further, when a power saving mode has been canceled, the reading of the documents cannot be performed immediately, resulting in a complicated document feeding device that is difficult to use. Further, in consideration of the recent trend for energy saving (power saving), there are increasing tendencies to set the document feeding device or the like in the power saving mode, and hence there is a high demand for improvement.
Note that, the above-mentioned conventional document feeding device and image forming apparatus are intended for accurately and easily performing the processing of returning from a paper jam or the like that has occurred in the course of a reading job. Therefore, the conventional document feeding device and image forming apparatus have no relevance to the problems related to the initial operation and to the mode regarding the power saving, and thus cannot solve the problems that the document feeding device and the image forming apparatus are difficult to use due to the unnecessary reset request.